Leber’s hereditary optic neuropathy (LHON) is an inherited form of vision loss. This condition usually begins in a person's teens or twenties, rare cases may appear in early childhood or later in adulthood. Males are affected much more often than females. Symptoms include eye pain or discomfort, numbness, tingling and clouding of vision. Predisposing factors include age, tobacco smoke, alcohol, cancer treating drugs, stress related chemicals, some antibiotics and cyanogens.